if the request is from an unauthenticated user, you should use wp_ajax_nopriv_(action)
to call the function, which in your case is:
add_action('wp_ajax_nopriv_cpm_add_update', array($this,'edit_added_people'));
if the request is from an unauthenticated user, you should use wp_ajax_nopriv_(action)
to call the function, which in your case is:
add_action('wp_ajax_nopriv_cpm_add_update', array($this,'edit_added_people'));